How to use mongoose Promise - mongo

In the current version of Mongoose, the exec() method returns a Promise, so you can do the following:

exports.process = function(r) {    return Content.find({route: r}).exec();}

Then, when you would like to get the data, you should make it async:

app.use(function(req, res, next) {     res.local('myStuff', myLib.process(req.path));     res.local('myStuff')         .then(function(doc) {  // <- this is the Promise interface.             console.log(doc);             next();         }, function(err) {             // handle error here.         });});

For more information about promises, there's a wonderful article that I recently read:http://spion.github.io/posts/why-i-am-switching-to-promises.html

Mongoose already uses promises, when you call exec() on a query.

var promise = Content.find( {route : r }).exec();

Mongoose 4.0 Release Notes

Mongoose 4.0 brings some exciting new functionality: schema validation in the browser, query middleware, validation on update, and promises for async operations.

With mongoose@4.1 you can use any promises that you want

var mongoose = require('mongoose');mongoose.Promise = require('bluebird');

Another example with polyfilling global.Promise

require('es6-promise').polyfill();var mongoose = require('mongoose');

So, you can just do later

Content  .find({route : r})  .then(function(docs) {}, function(err) {});

Or

Content  .find({route : r})  .then(function(docs) {})  .catch(function(err) {});

P.S. Mongoose 5.0

Mongoose 5.0 will use native promises by default if available, otherwise no promises. You will still be able to set a custom promises library using mongoose.Promise = require('bluebird');, however, mpromise will not be supported.